We are attempting to understand the mechanism of gene control in higher organisms by focusing on the expression of the gene that codes for alcohol dehydrogenase in Drosophila melanogaster. Using a variety of biochemical and molecular techniques, we are studying several mutants that lack alcohol dehydrogenase activity. One class of such mutants seems not to synthesize an alcohol dehydrogenase-like protein, even though these mutants have the Adh-gene and make substantial amounts of a mRNA that reacts with an Adh-gene probe. We are currently cloning all the representatives in this class of mutants and hope, by DNA sequencing, to determine what causes this molecular phenotype.